t^9,c4'/^ 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  125. 

L.  O.  HOWARD.  Entomologist  and  Chief  o(  Bureau. 


THE  FLORIDA  FERN  CATERPILLAR 


BY 


F.  H„  CHITTENDEX,  Sc.  D., 

In  Charge  of  Truck  Crop  and  Stored  Product  Insect  Investigations. 


I88ued  October  29,  1913. 


WASHINGTON: 

GOVERNMENT  PRINTING  OFFICE. 

1913. 


U.  S.  DEPARTMENT  OF  AGRICULTURE, 

BUREAU  OF  ENTOMOLOGY— BULLETIN  No.  125. 

L.  O.  HOWARD.  Entomologist  and  Chief  of  Bureau. 


THE  FLORIDA  FERN  CATERPILLAR. 


BY 


F.  H.  CHITTENDEN,  Sc.  D., 

In  Charge  of  Truck  Crop  and  Stored  Product  Insect  Investigations. 


Issued  October  29,  1913. 


WASHINGTON: 

GOVERNMENT  PRINTING   OFFICE. 

1913. 


BUREAU  OF  ENTOMOLOGY. 

L.  O.  Howard,  Entomologist  and  Chief  of  Bureau. 

C.  L.  Mabtlatt,  Entomologist  and  Ailing  Chief  in  Absence  of  Chief. 

R.  S.  Clifton,  Executive  Assistant. 

W.  F.  Tastet.  Chief  Clerk. 

F.  H.  Chittenden,  in  charge  of  truck  crop  and  stored  product  insect  investigations. 

A.  D.  Hopkins,  in  charge  of  forc.it  insect  investigations. 

W.  D.  Hunter,  in  charge  of  southern  field  crop  insect  investigations. 

F.  M.  Webster,  in  charge  of  cereal  and  forage  insect  investigations. 

A.  L.  Qttaintance.  in  charge  of  deciduous  fruit  insect  investigations. 

E.   F.   Phillips,  in  charge  of   bee   culture. 

A.  F.  Bubgess,  in  charge  of  gipsy  moth  and  brown-tail  moth  investigations. 

Rolla  P.  Curbie,  in  charge  of  editorial  work. 

Mabel  Colcobd.   in    charge  of  library. 

Tbuck  Cbop  and  Stored  Pboduct  Insect  Investigations. 

F.  H.  Chittenden,  in  charge. 

C.  H.  Popenoe.  Wm.  B.  Pabker.  II.  M.  Russell,  H.  O.  Mabsh,  M.  H.  High.  Fred 
A.  Johnston,  John  E.  Gbaf,  C.  F.  Staiil.  D.  E.  Fink.  A.  B.  Duckett.  F.  B. 
Millikex.  entomological  assistants. 

I.  J.  Condit.  R.  S.  Vaile,  collaborators  in  California. 

P.  T.  Cole,  collaborator  in  tidewater  Virginia. 

W.  -X.  Obd,  collaborator  in  Oregon. 

Thomas  H.  Jones,  collaborator  in   Porto  Rico. 

Mabion   T.   Van   Horn.   I'm  line   M    Johnson.   Anita   M.   Ballingeb,  Cecilia 
Sisco.  preparators. 
2 


CONTENTS. 

Page. 

Recent  injuries f» 

Descriptive 5 

The  moth 5 

The  larva 7 

The  pupa 8 

Distribution 8 

Injuries  and  habits 8 

Natural  enemies 10 

Methods  of  control 10 


ILLUSTRATIONS 


Fig.  1. — Florida   fern  caterpillar    (Eriopus  floridenais)  :   Moth  and  larvae 

at  work 

8884°-13  3 


Digitized  by  the  Internet  Archive 

in  2012  with  funding  from 

University  of  Florida,  George  A.  Smathers  Libraries  with  support  from  LYRASIS  and  the  Sloan  Foundation 


http://archive.org/details/floridafernOOunit 


THE  FLORIDA  FERN  CATERPILLAR. 
(Eriopus  fl'iridmxis  Gueii. ) 


RECENT    INJURIES. 

During  recent  years  a  species  of  caterpillar,  Eriopus  floridensis 
Guen..  native  to  Florida,  and  tropical  America  has  made  its  appear- 
ance in  injurious  numbers  in  northern  greenhouses,  notably  in  the 
District  of  Columbia,  in  Illinois,  and  in  Ohio.  It  is  apparently  re- 
stricted to  ferns,  on  which  it  feeds  naturally  in  its  occurrence  in  the 
open  in  the  warm  South,  and  it  has  undoubtedly  been  introduced 
into  northern  greenhouses  in  ferns  from  Florida.  It  is  a  compara- 
tively large  and  conspicuous  species  of  caterpillar  and,  though  not 
closely  related  to  the  true  cutworms,  has  the  same  habit  as  cutworms 
of  cutting  or  severing  portions  of  the  fern  plants,  apparently  de- 
strojdng  more  than  it  requires  for  food.  The  fern  growers  of  the 
District  of  Columbia  have  experienced  much  trouble  in  the  treatment 
of  this  species.  Some  have  had  good  results,  but  others  were  not 
able  to  cope  with  it  with  the  remedies  tried,  and  even  found  it  diffi- 
cult to  control  by  the  laborious  method  of  hand  picking.  Finally, 
however,  the  insect  has  yielded  to  this  method,  and  at  the  time  this 
was  written  (February.  1013)  it  was  not  to  be  found  except  in  one 
greenhouse  out  of  upward  of  a  dozen  inspected. 

DESCRIPTIVE. 
THE  MOTH. 

The  moth  (fig.  1)  belongs  to  a  group  of  noctuids  in  which  the 
forewings  bear  at  the  sides,  above  the  middle.' a  projecting  area  or 
tooth,  forming  an  outline  as  shown  in  the  figure.  The  hind-wings 
are  rather  broad  and  well  rounded  at  the  sides.  The  thorax  and 
abdomen  are  wide,  the  latter  especially  so  in  the  female.  The  color 
of  the  forewings  is  pale  brown,  marked  with  white  scales,  forming 
the  peculiar  and  attractive  pattern  shown  in  the  illustration.  The 
hind-legs  are  dull  buff,  edged  with  dusky  brown;  the  lower  surface 
is  paler. 

The  wing  expanse  is  about  H  inch  and  the  length  of  the  body 
about  half  an  inch. 

5 


6 


THE  FLORIDA  FERN  CATERPILLAR. 


The  following  description  is  copied  from  Sir  George  F.  Ham- 
son's  Catalogue  of  the  Noctuidse:1 

$.  Head  and  thorax  greyish  tinged  with  rufous  and  mixed  with  a  few  black 
scales;  palpi  thickly  irrorated  with  black;  frons  whitish  with  black  bar  above; 
antenna?  with  the  extremity  of  basal  joint,  the  basal  part  of  shaft  above  and 
below,  and  the  shaft  above  beyond  the  sinus  black:  te.guke  mostly  black,  edged 
With  grey,  with  angled  grey  line  near  base  and  grey  line  at  middle;  fore  and 
mid  tarsi  black  at  extremities;  abdomen  ochreous  tinged  with  fuscous,  the 
basal  crests  rufous,  the  crest  on  3rd  segment  black.  Forewing  ochreous  grey- 
ish tinged  with  rufous,  the  veins  defined  by  slight  blackish  streaks;  subbasal 
line  represented  by  double  black  stria?  filled  in   with  whitish  from  costa  and 


Fig.  1. — Florida  forn  caterpillar  (Eriopus  floridensls I  :  Moth  above;  striped  larva  at  left; 
dark   larva  at  right.      Enlarged.      i  Original,  i' 

cell  and  with  double  black  striae  before  it  from  cell;  antemedial  line  double, 
filled  in  with  whitish,  angled  outwards  below  costa,  acutely  angled  outwards 
on  base  of  vein  2,  then  excurved,  a  whitish  striga  before  it  from  submedian 
fold  to  vein  1 ;  orbicular  with  brown  centre  and  whitish  annulus.  very  narrow 
and  slightly  angled  outwards  at  median  nervure:  reniform  whitish  with  white 
bar  on  inner  edge  followed  by  a  brown  line,  oblique,  its  lower  extremity  pro- 
duced to  a  hook,  a  triangular  brown  patch  before  it  extending  to  costa  ;  an 
Oblique  brown  line  from  beyond  lower  edge  of  cell  to  vein  1.  then  bent  outwards 
to  inner  margin;   post  medial  line  double,  brown,   angled  inwards  below  costa, 


1  Cat.   Noct.   Brit.   Mus.,   vol.   7.   pp.   548-549,    London.    1908. 


DESCRIPTIVE.  7 

then  benl  outwards,  slightly  incim  imI  at  diseal  (did.  oblique  below  vein  4  and 
Incurved  at  submedian  told:  sub  terminal  line  whitish,  defined  on  inner  side 
by  a  triangular  brown  patch  from  costs  to  vein  (>.  angled  inwards  above  vein 
5,  then  outwards  to  termen  at  vein  4  and  defined  by  an  oblique  blackish  mark 
on  inner  side,  then  indistinct,  oblique,  waved,  with  a  sinuous  whitish  line 
before  it  ;  the  termen  red-brown  with  white  line  before  it  slightly  defined  by 
black  on  inner  side,  incurved  from  vein  7  to  4  where  it  angles  outwards,  then 
waved;  cilia  red-brown  with  yellowish  line  at  base.  Hind  wing  oehreous  whit- 
ish tinged  with  red-brown  especially  on  terminal  area;  a  slight  brown  dis- 
coidal  bar;  cilia  whitish;  the  underside  whitish,  the  costal  area  tinged  with 
oehreous  and  slightly  irrorated  with  brown,  a  brown  discoldal  bar,  postmedian 
line  bent  outwards  below  epsta,  then  crenulate,  traces  of  a  diffused  subterminal 
line,  three  small  black  spots  on  termen  below  apex  defined  by  whitish  on  inner 
side. 

9.  (J round-color  much  darker  red-brown. 

The  synonymy  is  as  follows: 

Eriopus  fioridensis  (Juenee.  Noct.,  vol.  2,  p.  292   (1852)  ;   Smith.  Cat.  Noct. 
X.  Amer..  p.  309. 

Eriopus  elegantulus  Herrich-Schaeffer,  Corresp.-Blatt.  zool.  min.  Ver. 

Regens,  1868.  p.  117. 
Callopistria  fioridensis  Guenee  (auct.). 

THE   LARVA. 

The  larva  (see  fig.  1)  is  slender,  with  forelegs  and  prolegs  normal 
and  well  developed.  The  head  is  small,  wider  than  long,  greenish 
in  life,  or  pale  yellow  in  inflated  specimens,  with  the  V-mark  strongly 
marked.  While  this  species  is  very  variable  in  general  color,  there 
is  one  characteristic  mark  which  extends  transversely  across  the 
anterior  border  of  the  thorax  in  a  blackish  line  and  abruptly  back- 
ward under  the  spiracles  to  the  second  thoracic  segment,  and  some- 
times nearly  to  the  anal  segment.  The  thoracic  plate  is  about  twice 
as  wide  as  long,  and  not  very  strongly  marked. 

The  general  color  varies  from  yellow  to  bright  green  to  dark, 
nearly  black.  In  the  palest  form  the  thoracic  border  may  extend 
nearly  to  the  third  joint  of  the  thorax  and  then  cease,  or  reappear  in 
short,  longitudinal  dashes  just  below  each  spiracle.  In  the  forms 
which  are  a  little  darker  these  lines  are  more  pronounced,  and  simi- 
lar transverse  dashes  mark  the  dorsal  surface  of  the  last  three  ab- 
dominal segments.  In  the  more  strongly  marked  form,  shown  in 
the  figure  at  the  left,  these  transverse  bands  are  of  a  maroon  color 
and  very  conspicuous.  In  most  forms,  and  especially  in  the  dark 
ones,  one  of  which  is  shown  at  the  right  in  the  figure,  there  is  a 
conspicuous  longitudinal  white  line  just  above  the  stigmata  or  spira- 
cles. This  is  almost  lacking  in  the  entirely  grown  forms.  These 
two  extreme  color  variants  are  so  different  that  if  observed  sepa- 
rately they  would  not  naturally  be  associated  with  the  same  insect, 
the  last  form  presenting  a  decidedly  velvety  appearance. 

The  length  is  If  inch  (33  mm.)  and  the  width  0.2  inch  (4  mm.). 


8  THE    FLORIDA    FERN    CATERPILLAR. 

THE  PUPA. 

The  pupa  is  robust,  of  the  usual  shining  mahogany-brown  color, 
the  posterior  apex  ending  in  two  minute  outcurved  spines.  The 
wing-pads  are  prominent. 

The  length  is  five-eighths  inch,  and  the  width  about  half  that. 

The  eggs  and  immature  stages  of  the  larva  have  not  come  under 
observation. 

DISTRIBUTION. 

The  type  locality  is  Florida.  Hampson  records  also  Mexico, 
Guatemala,  Costa  Rica,  Bahamas,  Jamaica,  Cuba,  Haiti,  Santa 
Lucia,  St.  Vincent,  Venezuela,  British  Guiana,  Brazil,  and  Trini- 
dad. The  species  is  also  recorded  from  Santo  Domingo.  It  is  obvi- 
ously a  neotropical  form  and  the  only  species  of  its  genus  occurring 
in  the  United  States. 

INJURIES  AND  HABITS. 

July  10,  1907,  this  species  was  reported  as  a  pest  by  Mr.  H.  M. 
Russell  (at  that  time  working  under  the  writer's  direction),  who 
observed  it  at  Orlando,  Fla..  attacking  the  fronds  of  potted  maiden- 
hair fern  in  that  vicinity.  It  was  noticed  that  the  larvge  usually 
fed  at  night,  although  sometimes  found  feeding  during  the  day. 
They  concealed  themselves  in  the  daytime  at  the  base  of  the  ferns 
or  were  found  resting  low  down  on  the  stems,  and  they  appeared  to 
have  a  habit  of  crawling  up  the  stems  and  eating  off  several  leaflets 
on  one  side,  thus  spoiling  the  beauty  of  the.  plants.  The  larvae 
observed  began  to  transform  to  pupae  August  1. 

During  September  of  the  same  year  Mr.  Bartos.  Mr.  J.  E.  Watson, 
and  Mr.  F.  H.  Kramer,  of  Anacost-ia.  D.  C.  made  complaint  that  this 
caterpillar  was  injurious  to  several  species  of  ferns  in  greenhouses. 
On  September  24  Mr.  C.  H.  Popenoe,  an  entomological  assistant  in 
this  bureau,  was  detailed  to  obtain  additional  specimens  and  make 
observations  on  the  habits  of  the  insect  and  the  conditions  of  the 
greenhouses.  Larvae  were  obtained  in  different  stages,  chiefly  between 
half-grown  and  nearly  grown  specimens.  They  were  feeding  in  the 
afternoon  on  the  upper  surface  of  the  leaves.  The  usual  method  of 
attack,  as  observed,  consisted  in  biting  off  the  midrib  leaf  one-half 
to  one-third  the  way  up.  Maidenhair  or  Adiantum  ferns  were  at- 
tacked either  by  biting  off  the  leaflets  at  the  tips  of  the  fronds  or 
by.  biting  off  the  entire  frond  about  1  inch  above  the  ground.  The 
majority  of  the  larvae  observed  were  resting  either  near  the  tip  of 
the  frond  of  the  midrib  or  else  concealed  in  the  stems  at  the  base 
of  the  plant.  An  entire  house  of  Adiantum  had  been  completely 
.-tripped  of  the  leaves  by  the  larva-,  and  one  grower  stated  that  his 


INJURIES   AND   HABITS.  9 

fern  crop  had  been  damaged  to  the  extent  of  $1,000.  It  was  stated 
that  the  larva  would  cut  the  plants  entirely  bare,  and  each  new  leaf 
would  be  attacked  by  two  or  three  larva1  as  soon  as  it  appeared. 
The  same  grower  stated  that  these  cutworms  troubled  his  ferns  the 
previous  year  and  that  larva?,  pupae,  and  imagos  were  seen  through- 
out that  winter  and  preyed  on  the  ferns  the  whole  year. 

July  3,  1908,  Mr.  J.  E.  Watson  called  at  the  office,  requesting 
methods  for  the  control  of  this  caterpillar,  which  was  doing  great 
injury  to  some  fern  plants  {Xephrolepis  whitmani)  in  the  green- 
house. He  estimated  that  damage  to  the  extent  of  $4,000  had  been 
caused  by  the  caterpillars  during  the  previous  year.  During  Sep- 
tember Mr.  Watson  and  Mr.  Bartos  made  another  complaint  of  this 
species.  Mr.  Duder,  another  florist,  also  complained  of  the  species. 
A  visit  was  made  on  September  '28,  1908,  and  a  number  of  larvae, 
mostly  full  grown,  some  about  to  pupate,  were  secured. 

The  larva  spins  a  loose  cocoon  by  drawing  together  dead  leaves  and 
particles  of  earth  next  to  the  ground.  It  sometimes  draws  together 
green  leaves  to  spin  the  cocoon.  Though  not  strictly  a  nocturnal 
feeder  it  shuns  bright  light  and  is  most  often  found  feeding  exposed 
in  the  early  morning. 

The  moth  is  seldom  seen  by  daj'  and  when  aroused  it  usually  flies 
down  under  the  benches  to  seclude  itself.  Thus  many  moths  are 
caught  in  spider  webs  that  abound  in  dark  corners  in  the  greenhouses. 

Since  the  ravages  by  this  species  were  repeated  in  1908  with  even 
greater  loss  than  in  1907,  two  growers  stated  that  unless  some  imme- 
diate steps  could  be  taken  to  check  the  pest  the  raising  of  ferns  in 
local  greenhouses  would  be  abandoned. 

The  caterpillars  seem  to  do  the  greatest  damage  early  in  the  year, 
especially'  during  May.  but  owing  to  the  uniformly  warm  temperature 
of  the  greenhouses,  winter  as  well  "as  summer,  there  is  no  time  when 
they  are  scarce  enough  to  allow  the  ferns  to  put  out  a  full  head  of 
fronds.  They  attack  the  tender  leaves,  especially  the  growing  tips 
of  young  fronds,  thus  checking  any  attempt  on  the  part  of  a  plant  to 
replenish  the  dying  fronds  with  a  new  growth,  and  so  far  stunting  it 
as  to  render  it  of  no  commercial  value. 

From  larvae  obtained  in  September  the  moths  began  to  issue  October 
26,  continuing  to  emerge  until  November  19.  The  pupal  stage  was 
ascertained  to  be  in  three  cases  23,  25.  and  27  days,  respectively,  in 
cool  October  weather. 

October  13,  1909.  Mr.  H.  Walter  McWilliams,  Griffin.  Ga.,  fur- 
nished  specimens  of  this  caterpillar,  found  on  ferns,  and  stated  that 
it  cuts  the  fronds  and  injured  the  sale  of  the  plants. 

January  18.  1910,  Mr.  John  J.  Davis1  reported  this  species  to  be  a 
serious  pest  on  greenhouse  ferns  in  Illinois.     It  was  first  reported 

1  Journ.  Econ.  Ent.,  vol.  3,  p.  183,  1010. 


10  THE    FLORIDA    FERN    CATERPILLAR. 

from  Onarga,  111.,  in  1907,  and  later  from  Chicago.  Incidentally  he 
mentioned  that  Mr.  A.  H.  Rosenfeld  believed  that  the  same  species 
occurred  on  ferns  in  Louisiana.  In  the  twenty-seventh  report  of 
the  State  entomologist  of  Illinois,  dated  1912  and  received  by  the 
writer  March  10,  1913,  after  the  present  bulletin  had  left  his  hands,  an 
article  appears  on  this  subject  by  Mr.  Davis,  who  is  now  in  the  em- 
ploy of  this  bureau.  He  mentions  injury  to  ferns  near  Chicago,  111., 
gives  notes  on  life  history,  and  adds  descriptions  of  all  forms,  with 
illustrations  of  larva,  pupa,  moth,  and  sexes.  In  remarks  on  remedies 
he  states  what  we  have  already  learned,  that  arsenicals  can  not  be 
applied  to  ferns  in  sufficient  strength  to  kill  this  so-called  cutworm, 
because  they  are  apt  to  adhere  to  the  surface  in  such  a  way  as  to  make 
it  difficult  to  handle  the  plants.  Poisoned  baits  are  also  mentioned, 
together  with  pyrethrum  and  nicotine  preparations. 

July  21,  1911,  Dr.  Thaddeus  McLaughlin,  Springfield,  Ohio,  fur- 
nished specimens  of  this  species,  stating  that  it  had  destroyed  some 
fine  ferns. 

What  appears  to  be  the  first  record  of  the  food  habit  of  this  species 
was  made  in  the  Yearbook  of  the  Department  of  Agriculture  for 
1908  (p.  578)  and  reads  as  follows: 

The  Florida  fern  caterpillar  (CaUopistria  floridensis  Guen.)  has  been  injuri- 
ous in  local  greenhouses,  one  florist  reporting  damage  to  his  ferns  to  the  extent 
of  $4,000. 

NATURAL   ENEMIES. 

Ichneumon  extrematis  Cress. — This  ichneumon  fly,  which  is  of 
moderate  size,  black,  lightly  marked  with  white,  was  reared  from  a 
pupa  of  the  Florida  fern  caterpillar  from  Anacostia,  D.  C,  Septem- 
ber 26,  1907.  It  was  seen  in  the  act  of  issuing  from  a  number  of 
pupal  cases,  showing  a  characteristic  exit  hole.  This  parasite  and 
two  other  species  were  seen  flying  about  the  infested  greenhouses. 

Sargaritis  sp. — This  small  ichneumonid  parasite  (Chttn.  No. 
211700)  was  reared  from  Eriojnis  floridensis  from  Anacostia.  D.  C., 
September  30,  1907. 

A  tachinid  fly  attacks  this  species,  a  single  specimen,  unidentified, 
having  issued  from  the  cocoon  of  its  host  August  22,  1907,  at  Orlando. 
Fla. 

METHODS  OF  CONTROL. 

Many  remedies  were  tried  by  the  growers  at  Anacostia,  some  of 
which  were  suggested  by  the  writer  and  others  by  different  persons 
in  the  city  of  "Washington.  Naturally  some  of  these,  which  were  not 
advised  by  entomologists,  did  not  produce  the  desired  effect. 

Hellebore. — September  20,  1907.  one  grower  sprayed  his  entire  crop 
with  a  strong  decoction  of  hellebore.  This  was  successful  in  driving 
away  the  larva*  but  it  scalded  the  foliage  of  the  ferns  so  badly  that 
many  of  the  plants  died.    He  was  advised  to  use  arsenate  of  lead. 


METHODS    OF    CONTROL.  11 

Poisoned  bait. — This  sumo  grower  employed  a  bait  of  poisoned 
bran  and  molasses,  about  as  advised  for  cutworms,  but  without  ma- 
terial effect,  the  caterpillars  preferring  the  ferns. 

Carbon  bisulphid. — Fumigation  with  carbon  bisulphid  was  tried 
by  Mr.  Watson  in  June,  1908,  but  he  stated  that  it  had  been  of  no 
avail  in  the  destruction  of  this  pest.  In  the  same  greenhouse,  in 
charge  of  Mr.  Watson,  strips  of  cloth  were  saturated  with  carbon 
bisulphid  and  placed  on  the  ground  about  the  plants,  but  although 
this  remedy  was  sometimes  successful  it  was  not  entirely  reliable 
since  the  caterpillars  had  necessarily  to  be  where  they  would  receive 
the  fumes  if  they  were  to  succumb. 

Hand  picking. — The  time-worn,  laborious,  but,  if  properly  pursued, 
effective  remedy  of  combating  the  insect  by  hand  measures  was  em- 
ployed by  numerous  growers.  One  of  these  reported  that  the  num- 
bers of  the  caterpillar  had  been  materially  reduced  by  hand  picking 
and  poisoning.  Another  grower  made  a  practice  of  going  over  the 
ferns  every  day  and  picking  off  all  the  caterpillars  that  could  be 
seen,  thus  reducing  the  numbers  of  the  pest  in  his  greenhouse.  It 
seemed  to  be  the  consensus  of  opinion  that  the  average  grower  would 
obtain  the  best  success  by  hand  methods,  one  of  the  best  methods 
consisting  in  shaking  each  individual  plant  over  the  ground  and 
trampling  upon  the  caterpillars  as  they  fall. 

Arsenate  of  lead. — Arsenate  of  lead  was  advised,  and  an  assistant 
was  detailed  to  an  infested  greenhouse  where  this  remedy  was  em- 
ployed, to  determine  the  extent  of  injury  and  to  advise  measures  for 
the  possible  extermination  of  the  cutworms.  On  his  arrival  he  was 
informed  that  several  thousand  had  been  hand  picked  from  the  ferns 
a  day  or  two  before  and  that  over  200  had  been  picked  from  a  space 
only  5  feet  square.  The  plants  had  also  been  sprayed  with  arsenate 
of  lead  at  the  rate  of  2^  pounds  to  50  gallons  of  water,  applied  twice, 
but  the  final  result  was  not  reported.  Some  of  the  growers  com- 
plained that  lead  arsenate,  when  used  in  a  solution  strong  enough  to 
kill  the  caterpillars,  would  at  the  same  time  leave  a  white  deposit  on 
the  plants  which  destroyed  their  commercial  value.  Owing  to  the 
delicacy  of  ferns  a  spray  of  Paris  green  strong  enough  to  kill  the 
caterpillars  would  also  burn  the  foliage.  Paris  green,  properly  com- 
bined with  Bordeaux  mixture,  should  not  produce  this  effect. 

Hydro  cyanic- acid  gas  fumigation. — Some  of  the  local  growers  were 
advised  by  the  writer  to  fumigate  with  hydrocyanic-acid  gas,  but 
it  was  not  tried,  so  far  as  can  be  learned.  If  fumigation  by  this 
method  were  employed  several  times  at  about  the  time  when  the 
insects  are  hatching  from  the  egg.  or  undergoing  their  molts,  it 
should  assist  very  materially  in  reducing  the  numbers  of  the  pest. 


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